U.S. patent application number 10/175537 was filed with the patent office on 2003-12-18 for combustion chamber system with obstacles for use within combustion-powered fastener-driving tools, and combustion-powered fastener-driving tools having combustion chamber system incorporated therein.
Invention is credited to Doherty, James E., Erden, Donald L.Van, Moeller, Larry M., Ricordi, Christian Paul Andre, Robinson, James W., Urban, Richard.
Application Number | 20030230256 10/175537 |
Document ID | / |
Family ID | 29549552 |
Filed Date | 2003-12-18 |
United States Patent
Application |
20030230256 |
Kind Code |
A1 |
Doherty, James E. ; et
al. |
December 18, 2003 |
Combustion chamber system with obstacles for use within
combustion-powered fastener-driving tools, and combustion-powered
fastener-driving tools having combustion chamber system
incorporated therein
Abstract
A combustion chamber system for use within a combustion-powered
fastener-driving tool, and a combustion-powered fastener-driving
tool having the combustion chamber system incorporated therein, is
disclosed. The combustion chamber system comprises a dual
combustion chamber system comprising a pre-combustion chamber and a
final combustion chamber. The pre-combustion chamber is
characterized a high aspect ratio and has different obstacles
fixedly incorporated therein for selectively retarding or enhancing
the rate of burn and the rate of speed of the flame front
propagating through the pre-combustion chamber. In a similar
manner, an obstacle having a predetermined solid geometrical
configuration is disposed within the final combustion chamber at a
position immediately disposed downstream of the port fluidically
interconnecting the pre-combustion chamber to the final combustion
chamber so as to effectively intercept the flame front and cause
the same to diverge and split into multiple components which flow
radially outwardly with a desirably accelerated rate of speed and
which traverse the entire diametrical extent of the final
combustion chamber. In this manner, all regions of the unburned
air-fuel mixture within the final combustion chamber are completely
and rapidly ignited. The controlled combustion effectively acts
upon the working piston with peak energy and power so as to drive
and discharge fasteners out from the tool and into predetermined
workpieces or substrates.
Inventors: |
Doherty, James E.;
(Barrington, IL) ; Robinson, James W.; (Mundelein,
IL) ; Urban, Richard; (Prospect Heights, IL) ;
Ricordi, Christian Paul Andre; (Bourg-Les-Valence, FR)
; Erden, Donald L.Van; (Wildwood, IL) ; Moeller,
Larry M.; (Mundelein, IL) |
Correspondence
Address: |
LISA M. SOLTIS
ILLINOIS TOOL WORKS INC.
3600 WEST LAKE AVENUE
GLENVIEW
IL
60025
US
|
Family ID: |
29549552 |
Appl. No.: |
10/175537 |
Filed: |
June 18, 2002 |
Current U.S.
Class: |
123/46R |
Current CPC
Class: |
B25C 1/08 20130101 |
Class at
Publication: |
123/46.00R |
International
Class: |
F02B 071/00 |
Claims
What is claimed as new and desired to be protected by Letters
Patent of the United States of America, is:
1. A combustion chamber system, for use within combustion-powered
fastener-driving tools, comprising: a pre-combustion chamber having
means defined within an upstream end portion thereof for initiating
combustion of an air-fuel mixture which propagates through said
pre-combustion chamber by means of a flame front; a final
combustion chamber fluidically connected by a port to a downstream
end portion of said pre-combustion chamber and having a working
piston operatively disposed at a downstream end portion thereof for
driving fasteners out from the tool and into a substrate; and first
obstacle means disposed within said pre-combustion chamber for
selectively enhancing and retarding the rate of burn of said
air-fuel mixture within said pre-combustion chamber, and the speed
at which said flame front propagates through said pre-combustion
chamber.
2. The system as set forth in claim 1, further comprising: second
obstacle means disposed within said final combustion chamber for
ensuring the rapid and complete combustion of said air-fuel mixture
within said final combustion chamber such that peak energy and
power can be impressed upon said working piston for driving
fasteners from the tool and into a substrate.
3. The system as set forth in claim 1, wherein: said pre-combustion
chamber has an aspect ratio, defined by means of the ratio of the
length dimension of said pre-combustion chamber relative to the
width dimension of said pre-combustion chamber, which is at least
2:1.
4. The system as set forth in claim 3, wherein: said pre-combustion
chamber has a coiled configuration wherein coiled portions of said
pre-combustion chamber are substantially coplanar with respect to
each other; and said aspect ratio is 30:1.
5. The system as set forth in claim 1, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises obstacle
means located within the vicinity of inner peripheral wall portions
of said pre-combustion chamber and extending substantially from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
6. The system as set forth in claim 5, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
continuous spiral-shaped rib member formed upon an internal
peripheral wall surface portion of said pre-combustion chamber and
extending substantially from said upstream end portion of said
pre-combustion chamber to said downstream end portion of said
pre-combustion chamber.
7. The system as set forth in claim 5, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of annular washers disposed at axially spaced positions
located along the longitudinal extent of said pre-combustion
chamber which extends substantially from said upstream end portion
of said pre-combustion chamber to said downstream end portion of
said pre-combustion chamber.
8. The system as set forth in claim 5, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of semicircular washers disposed upon diametrically
opposite side wall portions of said pre-combustion chamber and at
alternative axially spaced positions located along the longitudinal
extent of said pre-combustion chamber which extends substantially
from said upstream end portion of said pre-combustion chamber to
said downstream end portion of said pre-combustion chamber.
9. The system as set forth in claim 1, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises obstacle
means located along the longitudinal axis of said pre-combustion
chamber and extending substantially from said upstream end portion
of said pre-combustion chamber to said downstream end portion of
said pre-combustion chamber.
10. The system as set forth in claim 9, wherein: said first
obstacle means disposed within said pre-combustion chamber, for
retarding said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of pins extending transversely through side wall portions
of said pre-combustion chamber so as to be oriented substantially
perpendicular to the flow of said flame front through said
pre-combustion chamber and disposed at axially spaced positions
located along the longitudinal extent of said pre-combustion
chamber extending from said upstream end portion of said
pre-combustion chamber to said downstream end portion of said
pre-combustion chamber.
11. The system as set forth in claim 9, wherein: said first
obstacle means disposed within said pre-combustion chamber, for
retarding said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced orbs disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
12. The system as set forth in claim 9, wherein: said first
obstacle means disposed within said pre-combustion chamber, for
retarding said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced plates disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
13. The system as set forth in claim 9, wherein: said first
obstacle means disposed within said pre-combustion chamber, for
retarding said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced discs disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
14. The system as set forth in claim 2, wherein said second
obstacle means disposed within said final combustion chamber for
ensuring the rapid and complete combustion of said air-fuel mixture
within said final combustion chamber comprises: a solid geometrical
figure disposed within an upstream end portion of said final
combustion chamber and adjacent to said port fluidically
interconnecting said pre-combustion chamber to said final
combustion chamber for encountering said flame front propagating
from said pre-combustion chamber into said final combustion chamber
and for splitting said propagating flame front into radially
divergent flame front portions for combustibly igniting all regions
of said air-fuel mixture disposed within said final combustion
chamber.
15. The system as set forth in claim 14, wherein: said solid
geometrical figure comprises a cone wherein an apex portion of said
cone faces said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber.
16. The system as set forth in claim 15, further comprising:
divergent wall portions partially defining said final combustion
chamber and operatively cooperating with said solid geometrical
conical figure for defining annular flow channel portions within
which said split radially divergent flame front portions can
propagate with an enhanced rate of speed so as to achieve said
combustible ignition of all regions of said air-fuel mixture
disposed within said final combustion chamber while developing said
peak energy and power for impression upon said working piston for
driving the fasteners from the tool and into a substrate.
17. The system as set forth in claim 16, further comprising:
convergent wall portions partially defining said final combustion
chamber and disposed downstream from said divergent wall portions
partially defining said final combustion chamber for deflecting
combustion-generated pressure forces, power, and energy, developed
within said final combustion chamber, toward said working piston so
as to impact and move said working piston for driving the fasteners
from the tool and into a substrate.
18. The system as set forth in claim 14, wherein: said solid
geometrical figure is selected from the group comprising a cone, a
sphere, a plate, and a tear-drop.
19. The system as set forth in claim 18, wherein: when said solid
geometrical figure comprises one of said cone, sphere, and
tear-drop figures, wall portions, partially defining said final
combustion chamber, have geometrical configurations which
substantially correspond to the contours of side wall portions of
said one of said cone, sphere, and tear-drop figures so as to
operatively cooperate with said solid geometrical figure for
defining annular flow channel portions within which said split
radially divergent flame front portions can propagate with an
enhanced rate of speed so as to achieve said combustible ignition
of all regions of said air-fuel mixture disposed within said final
combustion chamber while developing said peak energy and power for
impression upon said working piston for driving the fasteners from
the tool and into a substrate.
20. The system as set forth in claim 14, wherein: said solid
geometrical figure has a transverse cross-sectional configuration
which is selected from the group comprising a circle, a pentagon, a
rectangle, a cross, and an irregular polygon.
21. A combustion-powered fastener-driving tool for driving
fasteners into substrates, comprising: a working piston for driving
fasteners out from said tool and into a substrate; a pre-combustion
chamber having means defined within an upstream end portion thereof
for initiating combustion of an air-fuel mixture which propagates
through said pre-combustion chamber by means of a flame front; a
final combustion chamber fluidically connected by a port to a
downstream end portion of said pre-combustion chamber and having
said working piston operatively disposed at a downstream end
portion thereof for driving the fasteners out from said tool and
into the substrate; and first obstacle means disposed within said
pre-combustion chamber for selectively enhancing and retarding the
rate of burn of said air-fuel mixture within said pre-combustion
chamber, and the speed at which said flame front propagates through
said pre-combustion chamber.
22. The tool as set forth in claim 21, further comprising: second
obstacle means disposed within said final combustion chamber for
ensuring the rapid and complete combustion of said air-fuel mixture
within said final combustion chamber such that peak energy and
power can be impressed upon said working piston for driving
fasteners from the tool and into a substrate.
23. The tool as set forth in claim 21, wherein: said pre-combustion
chamber has an aspect ratio, defined by means of the ratio of the
length dimension of said pre-combustion chamber relative to the
width dimension of said pre-combustion chamber, which is at least
2:1.
24. The tool as set forth in claim 23, wherein: said pre-combustion
chamber has a coiled configuration wherein coiled portions of said
pre-combustion chamber are substantially coplanar with respect to
each other; and said aspect ratio is 30:1.
25. The tool as set forth in claim 21, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises obstacle
means located within the vicinity of inner peripheral wall portions
of said pre-combustion chamber and extending substantially from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
26. The tool as set forth in claim 25, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
continuous spiral-shaped rib member formed upon an internal
peripheral wall surface portion of said pre-combustion chamber and
extending substantially from said upstream end portion of said
pre-combustion chamber to said downstream end portion of said
pre-combustion chamber.
27. The tool as set forth in claim 25, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of annular washers disposed at axially spaced positions
located along the longitudinal extent of said pre-combustion
chamber which extends substantially from said upstream end portion
of said pre-combustion chamber to said downstream end portion of
said pre-combustion chamber.
28. The tool as set forth in claim 25, wherein: said first obstacle
means disposed within said pre-combustion chamber, for enhancing
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of semicircular washers disposed upon diametrically
opposite side wall portions of said pre-combustion chamber and at
alternative axially spaced positions located along the longitudinal
extent of said pre-combustion chamber which extends substantially
from said upstream end portion of said pre-combustion chamber to
said downstream end portion of said pre-combustion chamber.
29. The tool as set forth in claim 21, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises obstacle
means located along the longitudinal axis of said pre-combustion
chamber and extending substantially from said upstream end portion
of said pre-combustion chamber to said downstream end portion of
said pre-combustion chamber.
30. The tool as set forth in claim 29, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of pins extending transversely through side wall portions
of said pre-combustion chamber so as to be oriented substantially
perpendicular to the flow of said flame front through said
pre-combustion chamber and disposed at axially spaced positions
located along the longitudinal extent of said pre-combustion
chamber extending from said upstream end portion of said
pre-combustion chamber to said downstream end portion of said
pre-combustion chamber.
31. The tool as set forth in claim 29, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced orbs disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
32. The tool as set forth in claim 29, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced plates disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
33. The tool as set forth in claim 29, wherein: said first obstacle
means disposed within said pre-combustion chamber, for retarding
said rate of burn of said air-fuel mixture within said
pre-combustion chamber, and said speed at which said flame front
propagates through said pre-combustion chamber, comprises a
plurality of axially spaced discs disposed along the central
longitudinal axis of said pre-combustion chamber extending from
said upstream end portion of said pre-combustion chamber to said
downstream end portion of said pre-combustion chamber.
34. The tool as set forth in claim 22, wherein said second obstacle
means disposed within said final combustion chamber for ensuring
the rapid and complete combustion of said air-fuel mixture within
said final combustion chamber comprises: a solid geometrical figure
disposed within an upstream end portion of said final combustion
chamber and adjacent to said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber for
encountering said flame front propagating from said pre-combustion
chamber into said final combustion chamber and for splitting said
propagating flame front into radially divergent flame front
portions for combustibly igniting all regions of said air-fuel
mixture disposed within said final combustion chamber.
35. The tool as set forth in claim 34, wherein: said solid
geometrical figure comprises a cone wherein an apex portion of said
cone faces said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber.
36. The tool as set forth in claim 34, further comprising:
divergent wall portions partially defining said final combustion
chamber and operatively cooperating with said solid geometrical
figure for defining annular flow channel portions within which said
split radially divergent flame front portions can propagate with an
enhanced rate of speed so as to achieve said combustible ignition
of all regions of said air-fuel mixture disposed within said final
combustion chamber while developing said peak energy and power for
impression upon said working piston for driving the fasteners from
the tool and into a substrate.
37. The tool as set forth in claim 36, further comprising:
convergent wall portions partially defining said final combustion
chamber and disposed downstream from said divergent wall portions
partially defining said final combustion chamber for deflecting
combustion-generated pressure forces, power, and energy, developed
within said final combustion chamber, toward said working piston so
as to impact and move said working piston for driving the fasteners
from the tool and into a substrate.
38. The tool as set forth in claim 34, wherein: said solid
geometrical figure is selected from the group comprising a cone, a
sphere, a plate, and a tear-drop.
39. The tool as set forth in claim 38, wherein: when said solid
geometrical figure comprises one of said cone, sphere, and
tear-drop figures, wall portions, partially defining said final
combustion chamber, have geometrical configurations which
substantially correspond to the contours of side wall portions of
said one of said cone, sphere, and tear-drop figures so as to
operatively cooperate with said solid geometrical figure for
defining annular flow channel portions within which said split
radially divergent flame front portions can propagate with an
enhanced rate of speed so as to achieve said combustible ignition
of all regions of said air-fuel mixture disposed within said final
combustion chamber while developing said peak energy and power for
impression upon said working piston for driving the fasteners from
the tool and into a substrate.
40. The tool as set forth in claim 34, wherein: said solid
geometrical figure has a transverse cross-sectional configuration
which is selected from the group comprising a circle, a pentagon, a
rectangle, a cross, and an irregular polygon.
41. A combustion chamber system, for use within combustion-powered
fastener-driving tools, comprising: a pre-combustion chamber having
means defined within an upstream end portion thereof for initiating
combustion of an air-fuel mixture which propagates through said
pre-combustion chamber by means of a flame front; a final
combustion chamber fluidically connected by a port to a downstream
end portion of said pre-combustion chamber and having a working
piston operatively disposed at a downstream end portion thereof for
driving fasteners out from the tool and into a substrate; and
obstacle means disposed within said final combustion chamber for
ensuring the rapid and complete combustion of said air-fuel mixture
within said final combustion chamber such that peak energy and
power can be impressed upon said working piston for driving
fasteners from the tool and into a substrate.
42. The system as set forth in claim 41, wherein said obstacle
means disposed within said final combustion chamber for ensuring
the rapid and complete combustion of said air-fuel mixture within
said final combustion chamber comprises: a solid geometrical figure
disposed within an upstream end portion of said final combustion
chamber and adjacent to said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber for
encountering said flame front propagating from said pre-combustion
chamber into said final combustion chamber and for splitting said
propagating flame front into radially divergent flame front
portions for combustibly igniting all regions of said air-fuel
mixture disposed within said final combustion chamber.
43. The system as set forth in claim 42, wherein: said solid
geometrical figure comprises a cone wherein an apex portion of said
cone faces said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber.
44. The system as set forth in claim 43, further comprising:
divergent wall portions partially defining said final combustion
chamber and operatively cooperating with said solid geometrical
conical figure for defining annular flow channel portions within
which said split radially divergent flame front portions can
propagate with an enhanced rate of speed so as to achieve said
combustible ignition of all regions of said air-fuel mixture
disposed within said final combustion chamber while developing said
peak energy and power for impression upon said working piston for
driving the fasteners from the tool and into a substrate.
45. The system as set forth in claim 44, further comprising:
convergent wall portions partially defining said final combustion
chamber and disposed downstream from said divergent wall portions
partially defining said final combustion chamber for deflecting
combustion-generated pressure forces, power, and energy, developed
within said final combustion chamber, toward said working piston so
as to impact and move said working piston for driving the fasteners
from the tool and into a substrate.
46. The system as set forth in claim 42, wherein: said solid
geometrical figure is selected from the group comprising a cone, a
sphere, a plate, and a tear-drop.
47. The system as set forth in claim 46, wherein: when said solid
geometrical figure comprises one of said cone, sphere, and
tear-drop figures, wall portions, partially defining said final
combustion chamber, have geometrical configurations which
substantially correspond to the contours of side wall portions of
said one of said cone, sphere, and tear-drop figures so as to
operatively cooperate with said solid geometrical figure for
defining annular flow channel portions within which said split
radially divergent flame front portions can propagate with an
enhanced rate of speed so as to achieve said combustible ignition
of all regions of said air-fuel mixture disposed within said final
combustion chamber while developing said peak energy and power for
impression upon said working piston for driving the fasteners from
the tool and into a substrate.
48. The system as set forth in claim 42, wherein: said solid
geometrical figure has a transverse cross-sectional configuration
which is selected from the group comprising a circle, a pentagon, a
rectangle, a cross, and an irregular polygon.
49. A combustion-powered fastener-driving tool for driving
fasteners into substrates, comprising: a working piston for driving
fasteners out from said tool and into a substrate; a pre-combustion
chamber having means defined within an upstream end portion thereof
for initiating combustion of an air-fuel mixture which propagates
through said pre-combustion chamber by means of a flame front; a
final combustion chamber fluidically connected by a port to a
downstream end portion of said pre-combustion chamber and having
said working piston operatively disposed at a downstream end
portion thereof for driving the fasteners out from said tool and
into the substrate; and obstacle means disposed within said final
combustion chamber for ensuring the rapid and complete combustion
of said air-fuel mixture within said final combustion chamber such
that peak energy and power can be impressed upon said working
piston for driving fasteners from the tool and into a
substrate.
50. The tool as set forth in claim 49, wherein said obstacle means
disposed within said final combustion chamber for ensuring the
rapid and complete combustion of said air-fuel mixture within said
final combustion chamber comprises: a solid geometrical figure
disposed within an upstream end portion of said final combustion
chamber and adjacent to said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber for
encountering said flame front propagating from said pre-combustion
chamber into said final combustion chamber and for splitting said
propagating flame front into radially divergent flame front
portions for combustibly igniting all regions of said air-fuel
mixture disposed within said final combustion chamber.
51. The tool as set forth in claim 50, wherein: said solid
geometrical figure comprises a cone wherein an apex portion of said
cone faces said port fluidically interconnecting said
pre-combustion chamber to said final combustion chamber.
52. The tool as set forth in claim 51, further comprising:
divergent wall portions partially defining said final combustion
chamber and operatively cooperating with said solid geometrical
conical figure for defining annular flow channel portions within
which said split radially divergent flame front portions can
propagate with an enhanced rate of speed so as to achieve said
combustible ignition of all regions of said air-fuel mixture
disposed within said final combustion chamber while developing said
peak energy and power for impression upon said working piston for
driving the fasteners from the tool and into a substrate.
53. The tool as set forth in claim 52, further comprising:
convergent wall portions partially defining said final combustion
chamber and disposed downstream from said divergent wall portions
partially defining said final combustion chamber for deflecting
combustion-generated pressure forces, power, and energy, developed
within said final combustion chamber, toward said working piston so
as to impact and move said working piston for driving the fasteners
from the tool and into a substrate.
54. The tool as set forth in claim 50, wherein: said solid
geometrical figure is selected from the group comprising a cone, a
sphere, a plate, and a tear-drop.
55. The tool as set forth in claim 54, wherein: when said solid
geometrical figure comprises one of said cone, sphere, and
tear-drop figures, wall portions, partially defining said final
combustion chamber, have geometrical configurations which
substantially correspond to the contours of side wall portions of
said one of said cone, sphere, and tear-drop figures so as to
operatively cooperate with said solid geometrical figure for
defining annular flow channel portions within which said split
radially divergent flame front portions can propagate with an
enhanced rate of speed so as to achieve said combustible ignition
of all regions of said air-fuel mixture disposed within said final
combustion chamber while developing said peak energy and power for
impression upon said working piston for driving the fasteners from
the tool and into a substrate.
56. The tool as set forth in claim 50, wherein: said solid
geometrical figure has a transverse cross-sectional configuration
which is selected from the group comprising a circle, a pentagon, a
rectangle, a cross, and an irregular polygon.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to a combustion
chamber system for use within combustion-powered fastener driving
tools, as well as the combustion-powered fastener-driving tools
having the combustion chamber incorporated therein, and more
particularly to a new and improved combustion chamber system for
use within combustion-powered fastener driving tools for driving
fasteners into workpieces or substrates wherein the combustion
chamber system comprises a pre-combustion chamber and a final
combustion chamber, wherein the pre-combustion chamber has an
aspect ratio, which is defined by the ratio of the length of the
pre-combustion chamber as compared to the width of the
pre-combustion chamber, which is at least 2:1 such that the
performance or output power levels of the combustion process can be
dramatically improved so as to effectively result in greater
driving forces, greater acceleration and velocity levels of the
working piston, and greater depths to which the fasteners can be
driven into their respective substrates, and wherein further,
predetermined or different types of obstacles are fixedly
incorporated within both the pre-combustion and final combustion
chambers for respectively optimally controlling, either by
increasing or retarding, the rate of burn and the speed at which
the flame jet or flame front not only propagates within and through
the pre-combustion chamber, but also the rate or speed at which the
flame front or flame jet enters the final combustion chamber, and
for ensuring that the entire unburned air-fuel mixture within the
final combustion chamber is in fact fully and rapidly ignited such
that a peak amount of pressure is effectively impressed upon the
working or fastener-driving piston in the shortest possible time so
as to in turn develop the desired amount of peak energy or power
for moving the piston-driver blade assembly for discharging the
fasteners from the tool and for driving the same into a particular
workpiece or substrate.
BACKGROUND OF THE INVENTION
[0002] Combustion-powered fastener-driving tools, for driving
fasteners into workpieces or substrates, are conventionally
well-known and are highly desirable within the industry in view of
the fact that they provide users with the ability to drive
fasteners into the workpieces or substrates independent of any cord
or hose attachments to remote power sources. These tools normally
comprise a combustion chamber, an on-board fuel supply, means for
igniting a combustible gaseous mixture within the combustion
chamber, and an expansion volume-driven piston having a driver
blade operatively connected thereto for driving fasteners out from
the tool and into the workpieces or substrates. It is further known
that the effective fastener-driving power for these tools is
dependent upon the initial absolute pressure of the combustible
gaseous mixture at the time of ignition, the rate at which the
gaseous mixture burns within the combustion chamber, the controlled
retarded movement of the piston while combustion takes place, and
the maximum combustion pressure that can be achieved. In view of
the fact that the burn rate is directly proportional to turbulence,
a first known type of combustion-powered fastener-driving tool
achieves a high burn rate by having a fan disposed within the
combustion chamber for the creation of turbulence. The burn rate is
therefore rapid enough such that a high combustion pressure level
can be desirably achieved within this tool before the piston-driver
blade assembly can move to a great degree.
[0003] A second known type of combustion-powered fastener-driving
tool utilizes a two or dual combustion chamber system comprising,
for example, a pre-combustion chamber and a final combustion
chamber, and wherein a one-way valve member is interposed between
the two combustion chambers so as to control the fluid flow between
the two combustion chambers whereby a higher maximum combustion
pressure is able to be achieved within the second or final
combustion chamber. The first or pre-combustion chamber has an
elongated configuration whereby the aspect ratio thereof, which is
defined as the ratio of the longitudinal length of the
pre-combustion chamber relative to the width or diametrical extent
of the pre-combustion chamber, is greater than two. As a result of
such structure, the unburned air-fuel mixture is forced ahead of
the flame front as it progresses from the upstream ignition end of
the pre-combustion chamber toward the downstream end of the
pre-combustion chamber within which the one-way valve member is
located. Combustion occurs within the second or final combustion
chamber when the flame front passes through the one-way valve
member into the second or final combustion chamber wherein the
final maximum combustion pressure achieved within the second or
final combustion chamber is directly proportional to the amount of
the combustible mixture pushed into the second or final combustion
chamber from the first or pre-combustion chamber. By constructing
the pre-combustion chamber with a relatively high aspect ratio, it
was discovered that more unburned fuel and air can be pushed ahead
of the flame front and into the final combustion chamber than was
previously possible with conventional combustion chamber systems
characterized by low aspect ratios, whereby the combustion pressure
within the final combustion chamber was elevated thereby leading to
more efficient combustion within the final combustion chamber and
the generation of higher operating pressures to be impressed upon
the working piston-driver blade assembly.
[0004] An example of such a dual combustion chamber system is
disclosed within the United States patent application entitled
COMBUSTION-CHAMBER SYSTEM WITH SPOOL-TYPE PRE-COMBUSTION CHAMBER
which was filed on Jan. 16, 2002 in the name of Donald L. Van Erden
et al. and assigned Ser. No. ______, the principles of which are
incorporated herein by reference. A third known type of
combustion-powered fastener-driving tool is substantially similar
to the second known type of combustion-powered fastener-driving
tool except that additional structure is incorporated within the
tool for positively restraining any movement of the piston until
the air-fuel mixture is ignited within the second or final
combustion chamber.
[0005] While the aforenoted combustion-powered fastener-driving
tools comprise and exhibit various positive structural and
operational features and have therefore obviously been commercially
successful, such combustion-powered fastener-driving tools also
have or exhibit several operational disadvantages or drawbacks. For
example, the use of a fan within the combustion chamber in order to
create the requisite amount of turbulence to accelerate the burn
rate of the air-fuel combustible mixture nevertheless requires a
drive motor. While small compact motors of the type required for
operation within such fastener-driving tools are commercially
available, the motors are expensive because they must be specially
designed and fabricated in such a manner as to be capable of
withstanding the repetitive jarring forces characteristic of the
fastener-driving operations. In addition, the motors also
experience periodic failure thereby requiring the tool to be
regularly serviced. In a similar manner, while the use of one-way
flow check valves at the aforenoted locations between the
pre-combustion and final combustion chambers in order to
effectively prevent pressure losses due to backflow from the final
combustion chamber to the pre-combustion chamber, the check valves
must also be specially designed so as to be light enough to permit
the unobstructed flow of both the unburned air-fuel mixture and the
propagating flame front in the forward direction, and yet be rugged
enough to be capable of resisting the high stresses imposed thereon
when it moves to its CLOSED position when combustion is initiated
within the second or final combustion chamber. In particular,
experience has shown that such valves often distort and deform
within relatively short periods of time or as a result of a
relatively small number of operational cycles thereby requiring
their frequent replacement. Lastly, while the piston-restraining
systems may exhibit optimal operational characteristics as
considered or viewed from a properly timed combustion point of
view, such systems obviously require the use of additional
components which add cost and weight factors to the tools, as well
as additional maintenance requirements.
[0006] In order to further attempt to control the generation of
turbulence within the combustion chamber, the burn rate of the
air-fuel mixture within the combustion chamber, and the propagation
flow rate of both the unburned air-fuel mixture and the flame front
within the combustion chamber, another type of conventional or
PRIOR ART combustion-powered fastener-driving tool is disclosed
within U.S. Pat. No. 4,773,581 which issued to Ohtsu et al. on Sep.
27, 1988. Briefly, as can be appreciated from FIG. 1, which
corresponds substantially to FIG. 1 of the noted patent, the
combustion-powered fastener-driving tool is seen to comprise a
cylindrical housing or cylinder head 1 wherein, for example, the
upper end of the housing or head 1 is closed while the lower end of
the housing or head 1 is open as at 1a. The cylinder head or
housing 1 effectively defines a combustion chamber 22, and a second
cylinder 2 is fixedly connected in a substantially coaxial manner
to the lower end of the cylinder head or housing 1 so as to
effectively define a piston chamber within which a piston 3 is
movably disposed. A cylindrical guide member 4 is fixedly connected
in a substantially coaxial manner to the lower end of the second
cylinder 2, and a fastener magazine 7, housing a plurality or strip
of fasteners 5, is fixedly attached to a side wall of the
cylindrical guide member 4 so as to permit the serial feeding of
the plurality of fasteners 5 into an internal guide bore 4a defined
within the guide member 4. An upper end portion of a fastener
driver or drive rod 6 is fixedly attached to the piston 3, while a
lower end portion of the fastener driver or drive rod 6 is
coaxially disposed within the guide bore 4a of the guide member
4.
[0007] Accordingly, when the piston 3 is forced downwardly under
combustion conditions initiated when the tool is fired, the
fastener driver or drive rod 6 will drive the leading fastener 5
through the guide bore 4a of the guide member 4 so as to be
discharged from the tool. In order to achieve combustion conditions
within the tool, a fuel supply device 8 is operatively connected to
an upper end portion of the housing or head 1 so as to inject fuel
into the upper end portion of the combustion chamber 22, and in a
similar manner, an air supply device 9 is likewise operatively
connected to an upper end portion of the housing or head 1 so as to
inject air into the upper end portion of the combustion chamber 22
whereby the air and fuel injected into the combustion chamber 22
will form an air-fuel mixture. A high tension generator 11, for
generating a high voltage discharge, is mounted upon the upper end
wall of the housing or head 1 and has a spark plug 12 operatively
connected thereto for generating an ignition spark when energized
by the generator 11. In order to enhance the turbulence and the
mixing together of the air and fuel components of the air-fuel
mixture charged into the combustion chamber 22, a plurality of
gratings or grilles 14a,14b,14c,14d are disposed within the
combustion chamber 22 so as to extend transversely across the
combustion chamber 22 and thereby be disposed within parallel
planes which are substantially perpendicular to the longitudinal
axis of the tool. Accordingly, the grilles 14a, 14b,14c,14d
effectively divide the combustion chamber 22 into sub-combustion
chambers 22a,22b,22c,22d,22e. In particular, each one of the
grilles or gratings 14a-14d may comprise, for example, a perforated
disc wherein a plurality of apertures 13 are effectively defined
between a network of wall portions 23.
[0008] In operation, when air and fuel have been injected into the
sub-combustion chamber 22a so as to form an air-fuel mixture, and
when such air-fuel mixture has effectively filled the entire
combustion chamber 22 as a result of movement or migration from
sub-combustion chamber 22a into sub-combustion chambers 22b-22e
through means of the apertures 13 respectively defined within the
gratings or grilles 14a-14d, the high tension generator 11 is
energized so as to in turn cause the spark plug 12 to generate an
ignition spark. As is known, when the spark ignites the air-fuel
mixture within the sub-combustion chamber 22a, the mixture burns
and a flame occurs. The resulting combustion gas within the
sub-combustion chamber 22a expands and forces the unburned mixture
toward the piston 3 through means of the apertures 13 defined
within the gratings or grilles 14a-14d. As the unburned mixture
successively passes through the apertures 13 defined within each
one of the gratings or grilles 14a-14d, the network of wall
portions 23 comprising the gratings or grilles 14a-14d effectively
form obstacles to the flow of such unburned mixture, and, in turn,
the obstacles effectively cause turbulence within the downstream
regions of the unburned mixture. Accordingly, as the flame also
traverses the grating or grille 14a through means of the apertures
13, and as a result of the turbulence generated within the unburned
air-fuel mixture, it is stated that the flame front advances at a
higher rate of speed within the sub-combustion chamber 22b. In
turn, the higher rate of speed of the flame front increases the
speed of expansion of the resulting combustion gas thereby also
increasing the speed of flow of the unburned mixture from the
sub-combustion chamber 22b to the sub-combustion chamber 22c.
[0009] As a result, stronger turbulence occurs within the unburned
air-fuel mixture present within the sub-combustion chamber 22c, and
in turn, the stronger turbulence within the unburned air-fuel
mixture present within the sub-combustion chamber 22c causes the
flame front to proceed or advance at a rate of speed which is
higher or greater than that present within the preceding
sub-combustion chamber 22b. Therefore, according to the disclosure
of such patent, it is also stated that the speed of the flame front
progressively increases each time it successively passes through
each one of the grilles or gratings 14a-14d. In this manner, the
rapid combustion of the air-fuel mixture is apparently ensured so
as to empower the piston 3 and the fastener driver or drive rod 6
whereby a leading one of the fasteners 5 can be driven out from the
tool and into the particular workpiece or substrate. It is
therefore noted that while the aforenoted PRIOR ART
combustion-powered fastener-driving tool of Ohtsu et al. comprises
the use of obstacle structures within the sub-combustion chambers
in order to advantageously successively or serially affect the
turbulence conditions, the burn rate of the air-fuel mixture, and
the propagation flow rate of both the unburned air-fuel mixture and
the flame front, within the plurality of sub-combustion chambers
22a-22e, it is submitted that the PRIOR ART combustion system of
Ohtsu et al. comprises a combustion system which effectively
exhibits a cascade type mode of combustion which is not truly
advantageous in connection with the promotion or development of the
aforenoted attributes or characteristics.
[0010] More particularly, in practice, the effectiveness of the
provision or presence of the successive orifice plates rapidly
deteriorates because each successive plate or screen actually
results, even briefly, in a momentary interruption of the
propagation speed of the flame front before it again regenerates
the turbulence needed to maintain or enhance the propagation speed
of the flame front. In addition, the structure of Ohtsu et al. does
not provide adequate separation of the unburned and burned
components of the air-fuel mixture. Advantageously, each plate
structure of Ohtsu et al. causes the flame front to be divided into
a plurality of segments or fingers which increases the surface area
so as to enhance the burn rate, however, the plates also tend to
cause the flame front or burning to proceed or occur laterally as
well as forwardly thereby mixing together the burned and unburned
components of the air-fuel mixture and causing dilution in the
burning properties of the system. Still further, it does not appear
that the combustion system of Ohtsu et al. viably achieves various
operational parameters which are deemed crucial or critical to
desired operational levels of current state-of-the-art
technological combustion-powered fastener-driving tools. More
particularly, the combustion system of Ohtsu et al. does not appear
to be concerned with a dual combustion chamber system, and does not
appear to be capable of optimally controlling, both in enhancement
and retardation modes, the rate of burn of the air-fuel mixture, as
well as the speed at which the flame jet or flame front not only
propagates within and through, for example, a pre-combustion
chamber of a dual combustion-chamber system, but in addition, the
speed at which the flame jet or flame front enters the final
combustion chamber. Still yet further, the system of Ohtsu et al.
also does not appear to comprise means for ensuring that the entire
unburned air-fuel mixture within the final combustion chamber is in
fact fully and rapidly ignited such that a peak amount of pressure
is effectively impressed upon the working or fastener-driving
piston, without any deleterious backward or reverse reflection
therefrom, so as to in turn develop the desired amount of peak
energy or power for axially moving the working piston-driver blade
assembly so as to discharge the fasteners from the tool and to
drive the same into a particular workpiece or substrate.
[0011] A need therefore exists in the art for a new and improved
combustion chamber system for use within a combustion-powered
fastener-driving tool, and a new and improved combustion-powered
fastener-driving tool having the new and improved combustion
chamber system incorporated therein, for optimally controlling,
both in enhancement and retardation modes, the rate of burn of the
air-fuel mixture, and the speed at which the flame jet or flame
front not only propagates within and through, for example, a first
pre-combustion chamber of a dual combustion-chamber system, but in
addition, the speed at which the flame jet or flame front enters
the second or final combustion chamber, and still further, a system
for ensuring that the entire unburned air-fuel mixture within the
second or final combustion chamber is in fact fully and rapidly
ignited such that a peak amount of pressure is effectively
impressed upon the working or fastener-driving piston, in the
shortest amount of time, without any deleterious backward or
reverse reflection therefrom, so as to in turn develop the desired
amount of peak energy or power for moving the working piston-driver
blade assembly so as to discharge the fasteners from the
combustion-powered fastener-driving tool and for driving the
fasteners into a particular workpiece or substrate.
OBJECTS OF THE INVENTION
[0012] Accordingly, it is an object of the present invention to
provide a new and improved combustion chamber system for use within
a combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein.
[0013] Another object of the present invention is to provide a new
and improved combustion chamber system for use within a
combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein, which
effectively overcomes the various operational drawbacks and
disadvantages characteristic of conventional or PRIOR ART
combustion-powered fastener-driving tools.
[0014] An additional object of the present invention is to provide
a new and improved combustion chamber system for use within a
combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein, which can
optimally control, both in enhancement and retardation modes, the
rate of burn and the speed at which the flame jet or flame front
not only propagates within and through, for example, a
pre-combustion chamber of a dual combustion-chamber system, but in
addition, the speed at which the flame jet or flame front enters
and progresses through the final combustion chamber.
[0015] A further object of the present invention is to provide a
new and improved combustion chamber system for use within a
combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein, which can
optimally control, both in enhancement and retardation modes, the
rate of burn and the speed at which the flame jet or flame front
not only propagates within and through, for example, a
pre-combustion chamber of a dual combustion-chamber system, but in
addition, the speed at which the flame jet or flame front enters
the final combustion chamber, and still further, which can ensure
the complete and rapid ignition of the entire unburned air-fuel
mixture present within the final combustion chamber.
[0016] A last object of the present invention is to provide a new
and improved combustion chamber system for use within a
combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein, which can
optimally control, both in enhancement and retardation modes, the
rate of burn and the speed at which the flame jet or flame front
not only propagates within and through, for example, a
pre-combustion chamber of a dual combustion-chamber system, but in
addition, the speed at which the flame jet or flame front enters
and progresses through the final combustion chamber, and still
further, which can ensure the complete and rapid ignition of the
entire unburned air-fuel mixture present within the final
combustion chamber such that a peak amount of pressure is
effectively impressed upon the working or fastener-driving piston,
without deleterious backward or reverse reflection therefrom, so as
to in turn develop the desired amount of peak energy or power for
moving the piston-driver blade assembly for discharging the
fasteners from the tool and for driving the same into a particular
workpiece or substrate. SUMMARY OF THE INVENTION
[0017] The foregoing and other objectives are achieved in
accordance with the teachings and principles of the present
invention through the provision of a new and improved combustion
chamber system for use within a combustion-powered fastener-driving
tool, and a new and improved combustion-powered fastener-driving
tool having the new and improved combustion chamber system
incorporated therein, wherein the combustion chamber system
comprises, for example, a dual combustion chamber system comprising
a first, upstream pre-combustion chamber and a second, downstream
final combustion chamber. The first, upstream pre-combustion
chamber is characterized by means of a high aspect ratio, as
defined by means of the ratio of the length of the pre-combustion
chamber relative to the width or diametrical extent of the
pre-combustion chamber, and has predeterminedly different obstacles
fixedly incorporated therein for either selectively retarding or
enhancing the rate of burn and the rate of speed of the flame jet
or flame front propagating through such first, upstream
pre-combustion chamber. More particularly, obstacles which either
extend in effect transversely or diametrically across the
pre-combustion chamber at different axial positions along the axial
or longitudinal extent of the pre-combustion chamber, or which are
disposed in effect substantially along the axial center of the
pre-combustion chamber at different axial positions along the axial
or longitudinal extent of the pre-combustion chamber, will tend to
retard or slow down the rate of burn and the rate of speed of the
flame jet or flame front propagating through the pre-combustion
chamber, while, alternatively, obstacles which are in effect
disposed in a substantially circumferential manner along the inner
periphery of the pre-combustion chamber, at different axial
positions along the axial or longitudinal extent of the
pre-combustion chamber, will tend to enhance or increase the rate
of burn and the rate of speed of the flame jet or flame front
propagating through the pre-combustion chamber.
[0018] In a similar manner, an obstacle having a predetermined
three-dimensional or solid geometrical configuration is disposed
within the second, downstream final combustion chamber at a
position immediately disposed downstream of the port fluidically
interconnecting the first upstream pre-combustion chamber to the
second downstream final combustion chamber. In this manner, as the
flame jet or flame front enters the final combustion chamber, the
flame jet or flame front effectively diverges and is split into
multiple sections or components which flow radially outwardly
toward the walls of the final combustion chamber, and which
therefore traverse the entire diametrical extent of the final
combustion chamber so as to thereby completely and rapidly ignite
all regions of the unburned air-fuel mixture present within the
final combustion chamber. The flame jet or flame front eventually
encounters the working piston, by which time the pressure forces
developed as a result of the rapid but controlled combustion within
the final combustion chamber can effectively act upon the working
piston so as to cause movement of the piston-driver assembly with
the desired peak energy and power so as to in turn cause the
particular fastener disposed within the guide tube of the tool to
be discharged and driven into the particular substrate or
workpiece.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Various other objects, features, and attendant advantages of
the present invention will be more fully appreciated from the
following detailed description when considered in connection with
the accompanying drawings in which like reference characters
designate like or corresponding parts throughout the several views,
and wherein:
[0020] FIG. 1 is a cross-sectional view of one type of conventional
or PRIOR ART combustion-powered fastener-driving tool;
[0021] FIG. 2 is a perspective view of a core member which is used
in connection with the molded fabrication of a pre-combustion
chamber, for use as part of a dual combustion chamber system within
a combustion-powered fastener-driving tool, wherein the
pre-combustion chamber has structural features which have been
uniquely developed in accordance with thee principles and teachings
of the present invention;
[0022] FIG. 3 is a top plan view of a pre-combustion chamber within
which a first embodiment of a combustion rate and flame jet
propagation enhancement obstacle structure in the form of a
continuous spiral or helical rib or boss formed upon internal
peripheral wall portions of the pre-combustion chamber and
extending throughout the axial or longitudinal length thereof, has
been incorporated in accordance with the principles and teachings
of the present invention, wherein the pre-combustion chamber is
fabricated from the mold core member illustrated within FIG. 2;
[0023] FIG. 4 is a schematic view of a second embodiment of a
combustion rate and flame jet propagation enhancement obstacle
structure, in the form of a plurality of axially spaced annular
washers formed or fixed upon internal peripheral wall portions of
the pre-combustion chamber so as to extend throughout the axial or
longitudinal extent thereof, which have been developed in
accordance with the principles and teachings of the present
invention;
[0024] FIG. 5 is a schematic view of a third embodiment of
combustion rate and flame jet propagation retardation obstacle
structure, in the form of a plurality of axially spaced pins,
plates, spheres, and the like, extending diametrically across the
interior of the pre-combustion chamber, or disposed at the axial
center of the pre-combustion chamber, and extending throughout the
axial or longitudinal extent thereof, which have been developed in
accordance with the principles and teachings of the present
invention;
[0025] FIG. 6 is a schematic elevational view of the new and
improved combustion chamber system constructed in accordance with
the principles and teachings of the present invention for use in
connection with a combustion-powered, fastener-driving tool,
wherein the combustion chamber system comprises a first
pre-combustion chamber fluidically connected to a second final
combustion chamber, and wherein further, a fourth embodiment of a
combustion rate and flame jet propagation enhancement obstacle
structure, in the form of a solid geometrical conical component,
has been incorporated within the second or final combustion chamber
so as to cause the division of the flame jet or flame front, coming
into the second or final combustion chamber from the first or
pre-combustion chamber, into a plurality of flame jet or flame
front components, and the divergence of such flame jet or flame
front components throughout the second or final combustion chamber,
so as to achieve the complete and rapid combustion of the entire
air-fuel mixture disposed within and throughout the second or final
combustion chamber;
[0026] FIGS. 7a-7h are schematic views showing differently
configured obstacles that can be disposed and utilized within the
second final combustion chamber in order to achieve the complete
and rapid ignition of all regions of the unburned air-fuel mixture
present within the final combustion chamber so as to in turn
develop peak energy and power characteristics for acting upon the
working piston-driver assembly; and
[0027] FIGS. 8a-8f are cross-sectional views, as taken along, for
example, line 8-8 of FIG. 7a, showing different cross-sectional
configurations which may be characteristic of or incorporated
within any of the various obstacles, as disclosed within FIGS.
7a-7h, that can be utilized within the second final combustion
chamber of the overall combustion-chamber system for use within the
combustion-powered fastener-driving tool.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0028] As has been noted within the aforenoted United States Patent
Application entitled COMBUSTION-CHAMBER SYSTEM WITH SPOOL-TYPE
PRE-COMBUSTION CHAMBER, which was filed on Jan. 16, 2002 in the
name of Donald L. Van Erden et al. and which has been assigned Ser.
No. ______, the interests of compact mechanical design have
resulted in PRIOR ART combustion systems, such as that disclosed
within the aforenoted Ohtsu et al. patent, which have a relatively
short axial length, and diameters or widths which are generally
much greater than their lengths. However, experiments performed in
connection with dual combustion chamber systems comprising first or
pre-combustion chambers, which are characterized by relatively high
length to width aspect ratios, and second or final combustion
chambers, has revealed the fact that relatively high aspect ratio
pre-combustion chambers are extremely effective at forcing unburned
air-fuel mixtures ahead of an advancing flame or jet front into the
second or final combustion chamber. In particular, the increased
amount of fuel and air pumped into the final combustion chamber
from an elongated pre-combustion chamber occurs in advance of a
flame front proceeding from the ignition end of the pre-combustion
chamber toward the discharge end of the pre-combustion chamber
which communicates with the final combustion chamber. This
structural arrangement increases the pressure within the final
combustion chamber before ignition occurs there, and this, in turn,
greatly increases the power which is obtainable or capable of being
derived from the combustion occurring within the final combustion
chamber. The improvement in power output from the final combustion
chamber can be increased in ratios equal to low integer numbers
simply by elongating the pre-combustion chamber wherein the same
has an optimum aspect ratio. More particularly, in accordance with
one of the principles and teachings of the present invention,
combustion chamber systems with elongated linear pre-combustion
chambers having length to width ratios over a broad range have been
tested and it has been noted that a significant improvement in
performance has been achieved when the aspect ratio is on the order
of as little as 2:1. More enhanced performance levels have been
achieved when the aspect ratio is within the range of 4:1 to 16:1,
with peak performance being achieved when the aspect ratio is
approximately 10:1. In addition, it has been noted that the
pre-combustion chambers can comprise oval, round, rectangular, or
other cross-sectional configurations whereby they will all function
desirably well as long as the length dimension of the
pre-combustion chamber is substantially greater than the average
width dimension thereof.
[0029] It has also been determined that in addition to the
elongated or linear pre-combustion chambers having the aforenoted
geometrical configurations, the elongated pre-combustion chambers
which are capable of generating substantially increased piston
power output can be curved, or folded, in effect, back onto itself.
Again, as long as the curved or folded pre-combustion chambers have
relatively high aspect ratios, the aforenoted performance
advantages will be able to be achieved. Still further, the
pre-combustion chambers can be formed from or comprise curved
sections that are joined in series, nested together, and/or
combined with linear or straight combustion chambers, or combustion
chamber sections so as to form compact assemblages which are
capable of achieving the objective advantages of the present
invention. It has been determined further that the output
performance of the elongated pre-combustion chambers can also be
influenced by means of aspect ratios concerning the width and
thickness dimensions of the pre-combustion chambers. For example,
an elongated pre-combustion chamber which has a rectangular
cross-section and which would therefore be expected to exhibit
enhanced output performance characteristics will fail to perform
well if the aspect ratio of the width to thickness dimensions is
relatively high. In other words, as the structure, shape, or
configuration of an elongated pre-combustion chamber approaches
that of a thin ribbon, it can become too constricted so as to
quench a flame front so that it is not possible to propagate. More
particularly, experiments have indicated that an optimal or
desirable width to thickness aspect ratio for successfully operable
elongated pre-combustion chambers is 4:1.
[0030] With the aforenoted discussion being considered, and
continuing further as a result of reference being made to FIG. 6,
the new and improved dual combustion chamber system, for use within
combustion-powered fastener-driving tools, is disclosed and is
generally indicated by the reference character 10. In particular, a
first upper pre-combustion chamber is disclosed at 12, and a second
lower final combustion chamber is disclosed 14. The downstream or
exhaust end of the pre-combustion chamber 12 is fluidically
connected to the upstream or intake end of the final combustion
chamber 14 through means of a port 16 defined within a wall 17
effectively dividing the first pre-combustion chamber 12 from the
second final combustion chamber 14, and the downstream or exhaust
end of the final combustion chamber 14 is operatively associated
with a working piston 18. The working piston 18 is disposed at a
START position within a cylinder head 20 of a combustion-powered
fastener-driving tool, and as is conventional, the cylinder head 20
forms an upstream portion of a cylinder housing, not shown, within
which the working piston 18 is movably disposed. The working piston
18 is, in turn, operatively connected to a driver blade, also not
shown, such that when the working piston 18 is moved downwardly
within the cylinder housing under the influence of the expanding
combustion conditions occurring within the final combustion chamber
14, the driver blade drives the leading one of the fasteners, as
forwarded from the tool fastener magazine into the tool guide tube,
not shown, through the guide tube and into the substrate or
workpiece.
[0031] In order to fabricate the first pre-combustion chamber 12 in
accordance with the principles and teachings of the present
invention, a spiral, coil, or helical-shaped core member 22, as
shown in FIG. 2, is utilized to mold or cast the pre-combustion
chamber 12 which is shown in more detail in FIG. 3. More
particularly, the core member 22 effectively comprises a male
member around which the female pre-combustion chamber 12 is
effectively molded or cast with the coiled portions thereof being
substantially coplanar. As can be readily appreciated from FIG. 2,
the male core member 22 has a radially outward upstream end portion
24 and a radially inward downstream end portion 26 which is
disposed substantially at or adjacent to the axial center of the of
the male core member 22. In this manner, when the female
pre-combustion chamber 12 is fabricated in accordance with molding
or casting techniques with respect to the male core member 22, the
upstream end portion 24 of the male core member 22 effectively
forms or defines an upstream intake or inlet end portion 28 within
the female pre-combustion chamber 12, while the downstream end
portion 26 of the male core member 22 likewise effectively forms or
defines an outlet or exhaust end portion 30 which is adapted to be
fluidically connected to the port 16 which fluidically
interconnects the pre-combustion chamber 12 to the final combustion
chamber 14 as illustrated within FIG. 6.
[0032] The upstream end portion of the pre-combustion chamber 12
additionally defines a housing portion 32 within which suitable
ignition generator and spark plug components, not shown, may be
housed for initiating combustion within the pre-combustion chamber
12, and it can be appreciated that upon initiation of combustion
within the pre-combustion chamber 12, the flame front or jet will
proceed along the longitudinally extending bore 33 defined within
the coiled or spiraled pre-combustion chamber 12, and in the
clockwise direction as denoted by means of the arrows F, so as to
move from the upstream intake or inlet end portion 28 thereof
toward the downstream outlet or exhaust end portion 30 thereof. As
a result of the coiled or spiraled configuration of the
pre-combustion chamber 12, it can be appreciated that in accordance
with one of the unique and novel structural characteristics of the
present invention, the structure of the pre-combustion chamber 12
is quite compact, and yet, in accordance with another one of the
unique and novel structural characteristics of the present
invention, the aspect ratio of the longitudinal length dimension of
the pre-combustion chamber 12 as compared to the width dimension or
diametrical extent of the pre-combustion chamber 12 is on the order
of, for example, 30:1.
[0033] In accordance with still another unique and novel structural
characteristic of the present invention, and with reference still
being made to FIGS. 2 and 3, it is seen that the male core member
22 comprises a rod or tubular member wherein the outer peripheral
wall portion has a predetermined outer peripheral diametrical
extent D.sub.1, and formed within the outer peripheral wall portion
of the core member 22 there is provided a continuous spiral or
helical-shaped groove 34 wherein the groove 34 has a predetermined
diametrical extent D.sub.2 which is less than the diametrical
extent D.sub.1 of the outer peripheral wall portion. Accordingly,
when the male core member 22 is used to fabricate the
pre-combustion chamber 12 by means of suitable molding or casting
techniques, it can be readily appreciated from FIG. 3 that the
interior peripheral wall portion 35 of the pre-combustion chamber
12, which defines the bore 33 of the pre-combustion chamber 12, has
a diametrical extent which is substantially the same as the
external diametrical extent D.sub.1 of the male core member 22. In
addition, it is noted that the inner peripheral wall portion or
bore 33 of the pre-combustion chamber 12 is provided with a
continuous spiral or helical-shaped rib or boss member 36 wherein
individual portions of the continuous spiral or helical-shaped rib
or boss member 36 are effectively formed or disposed at a plurality
of positions which are axially spaced along the longitudinal extent
of the bore 33 of the pre-combustion chamber 12 so as together
effectively form the continuous spiral-shaped boss or rib member 36
which has an inner diametrical extent D.sub.2 which corresponds
substantially to the outer or external diametrical extent D.sub.2
of the continuous spiral or helical-shaped grooved region 34 of the
male core member 22.
[0034] The purpose of providing the continuous spiral or
helical-shaped annular rib or boss member 36 upon the internal
peripheral wall portion 35 of the pre-combustion chamber 12 so as
to extend throughout the longitudinal extent of the pre-combustion
chamber 12 is that it has been discovered that the formation,
location, or placement of such rib or boss member 36, within the
vicinity of or adjacent to the interior peripheral wall portion 35
of the pre-combustion chamber 12, dramatically enhances the rate of
burn of the air-fuel mixture disposed within the pre-combustion
chamber 12 as well as the speed at which the flame jet or flame
front travels or propagates axially or longitudinally downstream
within the pre-combustion chamber 12. In a similar manner, and as
can best be appreciated from FIG. 4, in lieu of the continuous
spiral-shaped rib or boss member 36 being formed upon the internal
peripheral wall portion 35 of the pre-combustion 12, a plurality of
separate washer members can be fixedly disposed upon the internal
peripheral wall portion 35 of the pre-combustion chamber 12 at
axially or longitudinally spaced positions throughout the
longitudinal extent of the pre-combustion chamber 12, a plurality
of such washer members being disclosed, for example, at 38-46 along
only a limited axially or longitudinally extending portion of the
pre-combustion chamber 12. The disposition or use of such plurality
of axially or longitudinally spaced washer members achieves
substantially the same effect as the use of the continuous
spiral-shaped rib or boss member 36 in that the placement or
disposition of such annular washer members within the vicinity of
or adjacent to the interior peripheral wall portion 35 of the
pre-combustion chamber 12 likewise dramatically enhances the rate
of burn of the air-fuel mixture disposed within the pre-combustion
chamber 12 as well as the speed at which the flame jet or flame
front travels or propagates axially or longitudinally downstream
within the pre-combustion chamber 12.
[0035] Still yet further, in lieu of the individual annular washer
members, such as, for example, the washer members 38-46
schematically illustrated in FIG. 4, half-washer members may be
fixed upon diametrically opposite internal peripheral wall portions
of the pre-combustion chamber 12 and at alternative positions along
the axial or longitudinal extent of the pre-combustion chamber 12.
More particularly, for example, in lieu of completely annular
washer member 38, only a half-washer or semi-circular washer member
38' may be fixedly disposed at the particularly noted axial
position and upon an upper internal peripheral wall portion of the
pre-combustion chamber 12 as illustrated in FIG. 4, and in
conjunction with half-washer or semi-circular washer member 38',
additional half-washer or semi-circular washer members
40',42',44',46' may be fixedly disposed upon lower and upper
internal peripheral wall portions, respectively, of the
pre-combustion chamber 12. In this manner, it can be appreciated
that, in effect, a substantially spiral-shaped convex structure,
somewhat similar to the continuous spiral-shaped rib or boss member
36 as illustrated in FIG. 3, is formed so as to likewise
dramatically enhance the rate of burn of the air-fuel mixture
disposed within the pre-combustion chamber 12 as well as the speed
at which the flame jet or flame front travels or propagates axially
or longitudinally downstream within the pre-combustion chamber
12.
[0036] With reference now being made to FIG. 5, structure may
likewise be incorporated within the pre-combustion chamber 35 so as
to affect the rate of burn of the air-fuel mixture disposed within
the pre-combustion chamber 12, as well as the speed at which the
flame jet or flame front travels or propagates axially or
longitudinally downstream within the pre-combustion chamber 12, in
a manner which is effectively converse to the results achieved by
means of the aforenoted provision of the continuous spiral-shaped
rib or boss member 36 in conjunction with the internal peripheral
wall portion 35 of the pre-combustion chamber 12 as illustrated
within FIG. 3, or to the results achieved by means of the
aforenoted provision of the annular or semi-circular washer members
38-46,38'-46' in conjunction with the internal peripheral wall
portion 35 of the pre-combustion chamber 12 as is also illustrated
within FIG. 4. More particularly, a plurality of pins 48 are
fixedly mounted within axially spaced side wall portions of the
pre-combustion chamber 12 so as to extend transversely or
diametrically across the pre-combustion chamber 12 in such a manner
as to have an orientation which is substantially perpendicular to
the longitudinal axis of the pre-combustion chamber 12 and the
direction F of movement or propagation of the flame front or
jet.
[0037] In lieu of, or in conjunction with, the provision of the
plurality of transversely oriented pins 48 pins within the
pre-combustion chamber 12, a plurality of spheres, orbs, discs, or
plates 50 may likewise be disposed within the pre-combustion
chamber 12 at axially spaced positions disposed along the
longitudinal axis or axially central position of the bore 33 of the
pre-combustion chamber 12. As a result of the noted disposition and
orientation of the plurality of pins 48 or spheres, orbs, discs, or
plates 50 within the pre-combustion chamber 12, it has been
discovered or noted that the rate of burn of the air-fuel mixture
disposed within the pre-combustion chamber 12, as well as the speed
at which the flame jet or flame front travels or propagates axially
or longitudinally downstream within the pre-combustion chamber 12,
can be retarded.
[0038] Accordingly, by selectively choosing the number of pins 48
and spheres, orbs, discs, or plates 50 disposed within the
pre-combustion chamber 12, as well as the particular axial
positions at which the pins 48 and spheres, orbs, discs, or plates
50 are disposed within the pre-combustion chamber 12, different
degrees of retardation of the rate of burn of the air-fuel mixture
within the pre-combustion chamber 12, as well as the speed at which
the flame jet or flame front travels or propagates axially or
longitudinally downstream within the pre-combustion chamber 12, can
be achieved. Still further, it can readily be appreciated that in
accordance with the principles and teachings of the present
invention, the rate of burn and propagation speed retardation
structures 48,50, as illustrated within FIG. 5, can be structurally
combined with the rate of burn and propagation speed enhancement
structures 36 and 38-46,38'-46', as respectively illustrated within
FIGS. 3 and 4, so as to optimally control the air-fuel mixture rate
of burn and the flame jet or flame front propagation speed
characteristics of the pre-combustion chamber 12. It is critically
important to ensure that the flame front or flame jet propagation
speed is high enough such that when the flame front or flame jet
enters the final combustion chamber 14, ignition within the final
combustion chamber 14 occur in an optimum fashion.
[0039] With reference now being made to FIG. 6, the details of the
various structural components comprising the final combustion
chamber 14, in order to enhance or advantageously affect the
complete and rapid combustion of the air-fuel mixture disposed
within the final combustion chamber 14, as well as the propagation
speed of the flame front or flame jet, are disclosed. More
particularly, as has been noted hereinbefore, as a result of the
ignition of a portion of the air-fuel mixture within the
pre-combustion chamber 12, a flame front or flame jet propagates
through the pre-combustion chamber 12 and effectively pushes a
residual portion of the air-fuel mixture ahead of the flame front
or flame jet such that the residual air-fuel mixture and the flame
front or flame jet passes through the port 16 and enters the final
combustion chamber 14. In accordance with the unique and novel
principles and teachings of the present invention, and in order to
enhance or advantageously affect the complete and rapid combustion
of the air-fuel mixture within the final combustion chamber 14, as
well as the propagation speed of the flame front or flame jet, an
obstacle 52 is fixedly incorporated within the final combustion
chamber 14 so as to be disposed within the vicinity of or adjacent
to the port 16.
[0040] More particularly, the obstacle 52 comprises a solid or
three-dimensional geometrical figure which, as an example,
comprises that of a cone with the apex portion 54 thereof facing or
disposed adjacent to the port 16. In this manner, as the incoming
air-fuel mixture and flame front or flame jet enter the final
combustion chamber 14 from the pre-combustion chamber 12, the
air-fuel mixture and flame front or flame jet will encounter the
apex portion 54 of the conical obstacle 52 whereby the air-fuel
mixture and flame front or flame jet will effectively be divided
into a multiplicity of flows schematically illustrated as F.sub.1
and F.sub.2. It will of course be appreciated that in reality, the
original air-fuel mixture and flame front or flame jet will
effectively be divided into numerous flows, more than merely the
schematically illustrated flows F.sub.1 and F.sub.2, due to the
three-dimensional nature of the final combustion chamber 14 and
obstacle 52. In addition, it is further appreciated that the
upstream wall portions 56, partially defining the final combustion
chamber 14, diverge radially outwardly from the port 16, and
substantially correspond geometrically with the geometrical
configuration of the obstacle 52, so as to operatively cooperate
with the conical surface portion of the conically configured
obstacle 52 in effectively defining the flow channels 58 within
which the various fluid flows F.sub.1 and F.sub.2 can be conducted
in their aforenoted radially divergent manner. Accordingly, the
flow channels 58 are fluidically somewhat similar to the flow
channel defined within the bore 33 of the pre-combustion chamber 12
in that the fluid flow through the channels 58 is enhanced or
accelerated.
[0041] More particularly, as the flame front or flame jet traverses
or flows downstream from port 16 toward working piston 18, the
flame front or flame jet tends to adhere to or stay within the
vicinity of the internal surface portions of both the upstream wall
portions 56 of the final combustion chamber 14 and the obstacle 52,
as a result of well known boundary surface conditions or
properties, so as to effectively comprise an annular flame front or
flame jet which continually expands radially outwardly. In this
manner, the expanding flame front or flame jet effectively engulfs
or contacts the unburned air-fuel mixture throughout the final
combustion chamber 14 so as to in fact ignite the same. It is
further noted that downstream wall portions 60 of the final
combustion chamber 14 converge toward each other so as to
effectively conduct and deflect the combustion-generated pressure
forces, power, and energy, developed within the final combustion
chamber 14, toward the working piston 18 so as to impact the same
with the desired requisite amount of working energy and power. It
is to be appreciated that as a result of the use, disposition, and
presence of the conically shaped obstacle 52 within the upstream
end of the final combustion chamber 14, and furthermore, as a
result of the use, disposition, and presence of the conically
shaped obstacle 52 in combination with the obliquely oriented or
divergent upstream wall portions 56 of the final combustion chamber
14, the flame front or flame jet is able to fully encompass the
entire width or diametrical expanse of the final combustion chamber
14 so as to achieve the two critically important features or
characteristics of the combustion within the final combustion
chamber 14, that is, complete combustion of the air-fuel mixture
present within the final combustion chamber 14, and the combustion
of the same with the requisite amount or proper rate of speed.
[0042] It is to be particularly noted, for example, that if the
speed of the flame front or flame jet within the final combustion
chamber 14 is too slow, partial combustion of the air-fuel mixture
within the final combustion chamber will effectively occur so as to
initialize movement of the working piston prior to the combustion
process developing the peak power and energy for impacting upon the
working piston in order to derive peak power output in connection
with the driving of the fasteners through and out of the tool 10.
On the other hand, if the speed of the flame front or flame jet
within the combustion chamber 14 is too fast so as to complete its
passage through the final combustion chamber 14 without completely
igniting the entire air-fuel mixture within the final combustion
chamber, then, again, peak power and energy output cannot be
derived from the combustion process, and in addition, the flame
front or flame jet will be disadvantageously reflected, by means of
the working piston 18, back into the final combustion chamber 14
toward the port 16. This is not at all desirable in that it would
deleteriously affect combustion conditions within the final
combustion chamber 14, as well as negatively affect the
transmission of the pressure forces, power, and energy, developed
within the final combustion chamber 14, toward the working piston
18 whereby, in turn, adverse operational effects in connection with
the driving of the fasteners would correspondingly result.
[0043] With reference now being made to FIGS. 7a-7h, FIG. 7a
corresponds substantially to FIG. 6 in that FIG. 7a discloses the
use of a conically configured obstacle 52 within the upstream end
portion of the second final combustion chamber 14, and it is
particularly noted, for the instructional or disclosure purposes of
FIGS. 7a-7h, that in order to properly or optimally define the flow
channels 58 and the fluid flows F.sub.1 and F.sub.2 therethrough as
has been previously discussed, it is seen that the wall portions 56
have structural configurations or contours which substantially
correspond to those of the side wall portions of the conically
configured obstacle 52. Furthermore, in accordance with the
principles and teachings of the present invention, obstacles,
having geometrical configurations which are different from the
conical configuration of the obstacle 52, may be utilized within
the second final combustion chamber 14. More particularly, FIG. 7b
discloses an obstacle 152 which has a substantially conical
configuration, however, it is noted that in lieu of the conical
obstacle 152 having side wall portions which are linear, the
upstream side wall portions of the obstacle 152 are substantially
concavely curved while the downstream side wall portions of the
obstacle 152 are convexly curved. Correspondingly, it is noted that
the wall members 156 partially defining the final combustion
chamber 114 have configurations or contours which effectively match
those of the side wall portions of the obstacle 152 so as to
structurally cooperate with the side wall portions of the obstacle
152 so as to properly or optimally define or form the flow channels
158.
[0044] Continuing further, FIG. 7c illustrates an obstacle 252
which has a substantially spherical configuration, and
correspondingly, final combustion chamber upstream wall portions
256, partially defining the final combustion chamber 214, have
configurations or contours which effectively match those of the
side wall portions of the spherical obstacle 252 so as to
structurally cooperate with the side wall portions of the obstacle
252 in properly or optimally defining or forming the flow channels
258. Similarly, with reference being made to FIG. 7d, there is
illustrated an obstacle 352 which has a substantially conical
configuration, except that in lieu of the side wall portions being
linear, the side wall portions of the obstacle 352 are concavely
curved. Correspondingly, final combustion chamber upstream wall
portions 356, partially defining the final combustion chamber 314,
have configurations or contours which effectively match those of
the side wall portions of the conical obstacle 352 so as to
structurally cooperate with the side wall portions of the obstacle
352 in properly or optimally defining or forming the flow channels
358.
[0045] Still further, as illustrated within FIG. 7e, an obstacle
452 having a configuration which is substantially that of a flat
plate may be utilized within the final combustion chamber 414,
while as disclosed within FIG. 7f, an obstacle 552 is disclosed as
having a substantially teardrop configuration. Correspondingly,
final combustion chamber upstream wall portions 556, partially
defining the final combustion chamber 514, have configurations or
contours which effectively match those of the side wall portions of
the tear-drop obstacle 552 so as to structurally cooperate with the
side wall portions of the obstacle 552 in properly or optimally
defining or forming the flow channels 558. FIG. 7g discloses an
obstacle 652 which is substantially the same as the tear-drop
obstacle 552 as disclosed within FIG. 7f in that the same has a
substantially tear-drop shape or configuration, however, the
longitudinal orientation of the tear-drop obstacle 652 is
effectively reversed with respect to the orientation of the
tear-drop obstacle 552 as disclosed within FIG. 7f. Accordingly, it
can further be appreciated that final combustion chamber upstream
wall portions 656, partially defining the final combustion chamber
614, have configurations or contours which likewise effectively
match those of the side wall portions of the tear-drop obstacle 652
so as to structurally cooperate with the side wall portions of the
obstacle 652 in properly or optimally defining or forming the flow
channels 658 in a manner similar to, but reversed from, that of the
obstacle system shown in FIG. 7f. Lastly, as disclosed within FIG.
7h, an obstacle 752 having a configuration substantially similar to
that of the flat plate 452 of FIG. 7e, except that the upstream
face of the obstacle 752 disposed toward the port 716 has a concave
or crescent-shaped configuration, may likewise be used within the
final combustion chamber 714.
[0046] It is further noted that, in conjunction with both the flat
plate and crescent-shaped obstacles 452,752, such obstacles 452,752
are optimally located further downstream or away from the ports
416,716, than the corresponding disposition of the obstacles
52,152,252,352,552,652 relative to the ports 16,116,216,316,516,616
as respectively disclosed within FIGS. 7a-7d,7f, and 7g, in order
to effectively prevent undesirable rebound of the incoming flame
fronts back toward the ports 416,716, and to correspondingly permit
the divided fluid flows F.sub.1 and F.sub.2 to flow radially
outwardly toward the upstream final combustion side walls 456 and
756. It is further accordingly seen that the final combustion
chamber upstream side wall portions 456,756, partially defining the
respective final combustion chambers 414,714, have configurations
or contours which, while obviously not actually matching the
configurations or contours of the obstacles 452,752, nevertheless
effectively facilitate or promote the fluid flows F.sub.1 and
F.sub.2 within the flow channels 458, 758.
[0047] With reference lastly being made to FIGS. 8a-8f, while the
obstacle 52, as disclosed within FIG. 7a, may comprise, as has been
previously disclosed, a true geometrical cone such that the
cross-sectional configuration thereof as taken along the line 8-8
of FIG. 7a is that of a circle 852a as disclosed within FIG. 8a,
obstacles, while retaining an axial cross-sectional configuration
which would be similar to that of the cone 52, may be alternatively
configured such that the transverse cross-sectional configurations
thereof are no longer circular nad may comprise other geometrical
configurations. More particularly, an obstacle similar to that of
obstacle 52 may alternatively have transverse cross-sectional
configurations which selectively comprise, for example, a pentagon
as shown at 852b in FIG. 8b, a rectangle as shown at 852c in FIG.
8c, a cross or X as shown at 852d in FIG. 8d, a circle having
diametrical extensions as shown at 852e in FIG. 8e, and a suitable
irregular polygon as shown at 852f in FIG. 8f.
[0048] Thus, it may be seen that in accordance with the teachings
and principles of the present invention, there has been disclosed a
new and improved combustion chamber system for use within a
combustion-powered fastener-driving tool, and a new and improved
combustion-powered fastener-driving tool having the new and
improved combustion chamber system incorporated therein, wherein
the combustion chamber system comprises, for example, a dual
combustion chamber system comprising a first, upstream
pre-combustion chamber and a second, downstream final combustion
chamber, wherein the first, upstream pre-combustion chamber is
characterized by means of a high aspect ratio, and wherein the
pre-combustion chamber has predeterminedly different obstacles
fixedly incorporated therein for either selectively retarding or
enhancing the rate of burn and the rate of speed of the flame jet
or flame front propagating through such pre-combustion chamber. In
a similar manner, an obstacle having a predetermined
three-dimensional or solid geometrical configuration is disposed
within the second, downstream final combustion chamber at a
position immediately disposed downstream of the port fluidically
interconnecting the first upstream pre-combustion chamber to the
second downstream final combustion chamber.
[0049] In this manner, as the flame jet or flame front enters the
final combustion chamber, the flame jet or flame front effectively
diverges and is split into multiple sections or components which
flow radially outwardly toward the walls of the final combustion
chamber, and which therefore traverse the entire diametrical extent
of the final combustion chamber so as to thereby completely and
rapidly ignite all regions of the unburned air-fuel mixture present
within the final combustion chamber. The flame jet or flame front
eventually encounters the working piston, by which time the
pressure forces developed as a result of the rapid but controlled
combustion within the final combustion chamber can effectively act
upon the working piston so as to cause movement of the
piston-driver assembly with the desired peak energy and power so as
to in turn cause the particular fastener disposed within the guide
tube of the tool to be discharged and driven into the particular
substrate or workpiece.
[0050] Obviously, many variations and modifications of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the present invention may be practiced otherwise than as
specifically described herein.
* * * * *